A good question, they were instructed by God to be a light to the nations but they kept their own little light to themselves and then did not recognize the Light of the world when he came!

Because one is Born Jewish, one does not Become Jewish. Though it is possible for a non-Jew to lead a Jewish Life, their faith has no method/reason for conversion, and thus has no need to evangelize.

Perhaps history has shown them the "don't ask, don't tell" policy is safer.

In responce to one of the answers given, Christianity claims chosenness far more than Judaism does. Jews were called to be chosen, set apart, in that they must be a light to the nations. They are commanded to obey all rules and laws given by God (613 mitzvot), and 6 of which are given for the gentile to follow. It would be 100x easier for a gentile to get into heaven than would be a Jew if it were up to obeying the laws. The afterlife is not much mentioned in the Torah, but the ideas that I have become familiar with stated that God is infinately loving and forgiving. One day we will all see God, whether Jew or Gentile. But this is only after a purification process to rid us of our mistakes... There are many more mistakes for a Jew to make than a Gentile in regards to following the law. Therefore it is best that a Gentile remain remain a Gentile. But if a Gentile is fully committed to living a Jewish life and adopting the covenant his or herself, then a conversion is celebrated. But to go out in search of people to adopt the law is wrong, and will not produce those faithful. It is even an orthodox tradition that a potential convert is pushed away a number of times by the rabbi in order to test his willingness and determination... Those Christians on here spreading Christian theology should not have done so. This had to have been answered by one NOT attempting to preach the gospel at the same time.

Judaism believes that you don't have to be Jewish to be "ok" in G-d's eyes. Evangelizing assumes that people who don't share your religious beliefs are damned. Judaism doesn't believe that, it teaches that every moral person who believes in a single Higher Power is spiritually where they need to be.